Automatic material feed control for cereal comminuting apparatus



Oct. 20, 1953 F. TANNER 2,656,121

I I AUTOMATIC MATER FEED CONTROL FOR v CEREAL COMMI ING APPARATUS FiledDec. 2'7, 1949 2 Sheets-Sheet l Patented Oct. 20, 1953 AUTOMATICMATERIAL FEED CONTROL FOR CEREAL COMMINUT-ING APPARATUS Fritz Tanner,Sankt Gallen, Switzerland, assignor to Gebriider Biihlcr, Uzwil,Switzerland Application December 27, 1949, Serial No. 135,238 InSwitzerland April 14, 1949 1 Claim.

In all prior-art arrangements for automatically regulating the materialfed to the grinding rolls by means of a control device disposed in themill hopperand of a fluid-operated servomotor controlled thereby, whichact either on the feed segment or the number of revolutions of the feedrolls, the servomotor is mounted on the mill outside. Such dispositionrequires a rather long rigging between the control device in said.hopper and the servomotor precontrol means on one hand, and between theservomotor and the feed segment in the said hopper on the other hand.Due to such disposition, therefore, frictional losses and inaccuraciesarise in transmission, perhaps also a clogging or choking throughmaterial or foreign bodies being retained in said rigging, and alsohigher costs of manufacture. Finally it becomes rather difiicult tosubsequently incorporate such automatic material feed control means inexisting mill units of older construction in that, as a rule,substantial structural changes have to be made in the hopper and in therigging to the feed segment, and the mill unit casing has to be drilledfor the passage of rigging shafts. By rigging is understood a leverconnection associating the controller and the servomotor.

All the said deficiencies shall be avoided by means of my presentinvention in that the hopper control means and servomotor are combined,

without any rigging, to a unit which is mounted directly in the hopper.

The improvement consists in the combination of a controller, aservomotor, and means controlling the servomotor directly by thecontroller, without any such rigging, the controller and servomotorforming a structuralunit disposed directly in the hopper, above thecereal feed valves, the servomotor operating directly upon said valveson the action of said controller. And a preferred form is to have theservomotor piston co-axial with the stem of the controller, so that thedirection of movement of the servomotor axis coincides with that of thecontroller stem.

The invention will be further described, an embodiment shown in thedrawings, and the invention will be finally pointed out in the claim.

A known non-automatic material feed control means and one form of mypresent invention are the present invention. In a twin mill unitembodying this invention,the left hand side is the same as the righthand, except in reverse. The

left hand side of Fig. 1, is shown to indicate the known, structure forthe purpose of having the right hand side point out the novelty of thepresent invention over the old; and

Fig.2 shows a vertical section through the hopper feed control means ofFig. 1, but in a much larger scale.

Similar characters of reference indicate correspending parts throughoutthe various views.

, ,In Fig. l, the grindingrolls are designated by l, and the feed rollsby 2. In the left side of Fig. 1, the segmental feed gate? is pivoted at4 and rigidly connected to an arm 5 which co-acts with an arm I. Thelatter passes through an aperture 1 inthe hopper partition 8 and issecured to a pin E which controls the width In over the entire length ofthe mill unit and biases the feed gate ,3 through the arms I and 5. Thegate 3 is kept in balance against the pressure of the material throughits own weight, if required a spring means may be used for equalizingthe said pressure. The more material is moving down the hopper, the

- higher the gate 6 is loaded and the more the gate he opened. The armsI and 5 form a linkage be- 1 tween the gate 6 andthe feed gate 3. In theimproved form, said arms I and 5 form a linkage between the arms 6 andthe feed gate 3.

In the right side of Fig. 1, the segmental feed gate 3, the arms5 and 1,and the partition 8 are similarly constructed asin the left side of jFig.1. In place of the gate 6 forming the con- 1 troller in the leftside of Fig. l, a narrow arm 5 is provided, which may consist of a fiat.

arm 6' coacts with a roller H of a servomotor 12 which issecured,adjustably in elevation, to

The

the center wall of the mill unit casing by means of a holder 13. Theservomotor I2 is operated by I means of compressed air supplied througha pipe shown in the accompanying'drawings, in which- I4 extending fromthe outside of the hopper. A

controller 15 is mounted on the servomotor I 2.

The feed rolls 2 have one roll higher than the otherand the upper one isspaced from the lower end of the hopper wall In this space a segmentalfeed gate '3 moves to open the space or to close it, depending on theposition of the roller ll of the extending end of the piston of saidservomotor l2. The position of the feed gate 3 controls the amount ofmaterial over the feed rolls 2 flowing to the grinding rollers I.

As shown in Fig. 2, a piston I! with a sealing sleeve I8 is disposed inthe cylinder it of servomotor [2. The piston I1 is loaded by a spring 19which tends to push the piston upwardly against a plug 20. The roller II coacting with arm 6 is mounted on the foot end of piston I1. A guidebush 2! is screwed into the head of piston I! and has an axial bore 22which co-acts with a control pin 23 of controller l5. When the pin 23 isin the position shown in Fig. 2, in which the controller I5 is notloaded, the compressed air entering through pipe 14 into cylinder i6escapes to the outside through the bore 22 and a plurality of holes2l-25 in piston H, I case remains in its topmost position, and the gate3 is closed. 7

When, however, the controller I5 is loaded, the pin 23 is depressed andcloses bore 22. The compressed air entering through pipe l i depressespiston IT, and gate 3 is swung open by means of roller H and arms 6', l.and 5. I

At the lower end of piston I! a set collar 2'3 and bellows 28 areprovided, which latter form a sealing means against the ingress ofmaterial into servomotor iii. For the same purpose, bellows 29 areprovided between servomotor l2 and controller l5.

The axis of the servomotor l2 which is coincident with the axis of itspiston I! is vertically aligned with the axis of the controller shaft orpin 35.

The controller l5 comprises a vertical tubular stem as which on top isclosed through a plug 30, and sheet-iron gable members 3|. To the headof stem 30 a bolt 32 is secured which has a ball-shaped foot 33 and isretained in a bush 3t. The latter is secured to a coupling pin 35 whichthus is articulated to the bolt 32 and connected to stem 36. Thecoupling pin 35 on its foot carries a bush 3% which retains theball-shaped head 3? of the control pin 23. A piece of gas pipe 38threaded over substantially its entire length, is screwed in the plug ofservomotor cylinder Ill and carries a nut 39 which serves for adjustingthe force of a spring 4i When feeding a specifically lighter material,nut 39 is moved down wardly, thereby reducing the spring force. Whenfeeding, a heavier material, nut 39 is moved upwardly, therebyincreasing the spring force.

When the controller i5 is not loaded by material in the hopper, piston16 and guide bush due to the force or pressure of spring I9 is in thetopmost position in which the bush 2! abuts against plug 28. Thecompressed air entering through the pipe M then escapes to the outsidethrough the bores 22 and 2426 in piston [1.

When, however, the controller I5 i weighted through the material, thestem is depressed through the gable members 3! against the action ofspring it, the control pin 23 being taken along and covering the bore22. The compressed air entering the servomotor through pipe M, thendepresses piston ll, thereby opening the segmental swing gate 3 throughthe roller II and the arms 8, l and 5. The gate 3 is still furtheropened on increasing the feed of material, and closed on decreasing thesame. In normal operation, the control pin 23 always substantiallycloses the bore 22 entirely, until the piston l1 abuts on tops againstthe plug 20 and the compressed air escape to the atmosphere.

The latter in such The automatic control means described may be mountedin all mill units practically without any structural change of theexisting material feed controller means. It also permits to efiect thethrowing in and out of gear of the grinding rolls and the feed rolls,without requiring a second pipe line to the interior of the mill unitbesides the line H. In such latter case, the power cylinder effectingthe said movement is mounted directly to the manually-operated controllever of the mill unit. My present invention also affords advantageswhen regulating the material feed through adjusting the number ofrevolutions of the feed rollers, since here also the rigging from thecontroller to the precontrol is eliminated. The rigging from theservomotor to the revolution governer is not so easily disturbed throughthe material in the hopper, since substantial forces are available forthe servomotor.

What I claim as new and desire to secure by Letters Patent, is:

In an automatic feed control means 'for cereal comminuting apparatushaving grinding rollers, feed rolls, one higher than the other, and bothabove the grinding rollers, a hopper having walls above said feed rolls,the lower end of a hopper wall being spaced from said higher feed roll.a segmental feed gate between said higher roll and said lower end ofsaid hopper for controlling the amount of material to said feed rolls,the combination of an arm transverse to the hopper havin one end hingedto a wall of the hopper, linkbetween said arm and said feed gate, toopen said feed gate when said arm is in a downward position and closesaid feed gate when the arm is in its upper position, a servomotorhaving a piston in hopper, one end of the piston extending out of saidservomotor, a fluid supply pipe extending from said servomotor within tothe outside of said hopper, a bracket secured to the innor wall of saidhopper for supporting said servomotor within said hopper in the path ofthe cereal feed flow, said servomotor having an axis vertically alignedwith its said piston, and a controller within said hopper above saidservomotor having laterally extending vanes for supporting cerealandhaving a vertical shaft for said vanes, said shaft extending from saidcontroller into said servomotor for regulating the fluid supply to saidservomotor and the consequent position of its said piston on said arm,said controller shaft having an axis vertically aligned with said axisof said servomotor, forming a structural unit. whereby when cereal inthe said hopper weights said controller vanes over a balanced amount,said shaft descends into said servomotor to compel said supply fluid tomove the servomotor piston and said arm downwardly and by said linkageto open said feed gate, and when the cereal on said vanes is less thansaid weighted amount, the servomotor supply fluid is shut off and saidgate closes against any feeding of said material to said feed rolls andto said grinding rollers.

FRITZ TANNER.

Name Date Moog Sept. 9, 1930 Number

